This invention relates to a method and apparatus for locating a point in space relative to a fixed datum base.
Before a damaged motor vehicle can be repaired, it is necessary to determine the extent to which the location of various datum points on the vehicle deviate from manufacturer's specifications. Repair is then achieved by reforming damaged portions of the vehicle until all datum points have been returned to correct relative positions. The proper repair of body damage is particularly important in vehicles of the so-called unibody construction since accurate body alignment is essential for correct vehicle suspension and steering.
Systems for measuring the damage or misalignment of vehicle bodies are commonly called measuring bridges. One such assembly includes a fixed frame having a plurality of support fixtures for engaging key datum points on the vehicle whereby the latter is supported relative to a fixed datum plane. With the vehicle supported in this manner, fixtures are employed for determining whether reference points on the vehicle are located in correct three dimensional positions relative to this datum plane. These points include, for example, the shock towers in the rear of the vehicle and the McPherson strut mountings in the front. The locations of these points differ in vehicles of different manufacturers and between different vehicle models of the same manufacturer. As a result, prior art measuring bridges require a different set of measuring fixtures for substantially each automobile model and body style. This substantially increases the cost of such systems, particularly as a result of a proliferation of new models which require the continued acquisition of additional fixtures.